Visual Composer Stopped Working after 4.5 update – possible fix

Like many I have had a problem with Visual Composer not loading after the 4.5 update. The theme is up to date for 4.5 the bundled VC was also updated with the theme update. I cleared all cache, flushed cloudflare, etc…. Theme developer logged in from his location and no problems

Through much trial and error, the only way I can get it to work is by opening an incognito window in chrome and logging in. VC works flawlessly then.

Any clues why this is happening and how to fix this at all?

Thanks for any input